Getting Started with Calibre


Getting to know new tools can feel daunting, which is why we created this guide to help you get started and be successful in establishing a reliable performance monitoring system. You can always explore all features or contact our friendly support team if you have any questions.

Step 1: Add your sites to Calibre

To add a site, choose from 14 global test locations, add a name, provide a URL to be tested and set a testing schedule. Calibre allows you to check unlimited sites and pages, without any extra cost.

After creating the site, you’ll be able to configure its settings, such as where it’s tested from, how often, under which Test Profiles, add additional pages and more.

The initial test runs six consecutive snapshots to provide the most reliable results. You will be emailed when results are ready to be viewed.

Step 2: Configure test environments

When you have successfully added sites and pages to track, it’s time to determine under what conditions they will be tested. Test Profiles allow you to set up a combination of testing scenarios that cover a wide range of user experiences.

You can emulate devices, network speeds, authenticate into your applications, disable ads or specific third party vendors. Calibre will automatically create two baseline Test Profiles for you:

  • Chrome Desktop with a Cable connection
  • Motorola Moto G4 with a regular 3G connection

These two Test Profiles will show an accurate portrayal of two opposite ends of the performance spectrum, based on global averages. Mix and match settings to create comprehensive user testing scenarios relevant to your audience. We especially recommend disabling ads and testing without third parties.

Step 3: Set Performance Budgets

Budgets are a great way of making sure that when the performance of your sites deteriorates, you will be instantly notified and able to act on regressions. You can set budgets against any metric available in Calibre and apply them to specific pages and Test Profiles.

You can be notified when a budget is met or blown in two ways: through email or Slack alert posted to a chosen channel.

It’s a great idea to create a dedicated a general #performance-metrics channel or a dedicated #projectName-alerts channel so your entire team can keep an eye on speed improvements and regressions.

We recommend starting with setting budgets against several metrics that describe user experience most accurately, such as:

It’s also worth keeping an eye on the Lighthouse Performance Score as it not only provides a more high-level view of performance but also contributes to how your sites are ranked in Google.

Step 4: Enable Insights reports

Knowing how your metrics change over time lies at the heart of successful performance monitoring. Calibre does the heavy lifting and generates a weekly or monthly Insights report for each of your sites that you can opt into.

Insights will provide crucial information on performance trends through showcasing pages and metrics with the most significant changes.

To increase the visibility of the performance changes included in the reports, you can forward them to relevant teammates who aren’t Calibre users or create a dedicated mailing list.

Step 5: Set up Pull Request Reviews

A majority of performance regressions are preventable when using pre-production monitoring. With Pull Request Reviews, you’re able to see the performance impact of your work before it affects your customers.

Each review will showcase changes in critical metrics: Lighthouse Performance Score, First Contentful Paint and Time to Interactive. It will also highlight the most significant changes in metrics and budgets on a per-page basis.

A comprehensive comparison of your production (or staging) environment and the changes made in the Pull Request will be posted as a comment, accessible to anyone using GitHub. You can enable Pull Request Reviews for any selected site.

To leverage Pull Request Reviews, you need to be using GitHub and one of the supported deployment methods, such as ZEIT, Netlify, Heroku or GitHub deployment statuses.

Step 6: View the results

There are several ways to view performance data in Calibre. First one is the Pulse page, which showcases historical metric data trends across Test Profiles, including markers for when deploys happened. Metric graphs can be reordered and explored further to investigate 6, 3, 1 month and 7-day averages.

Snapshot Overview provides the most performance information:

  • critical performance metrics
  • a render timeline
  • a JavaScript main thread execution timeline
  • assets transferred by type graph
  • request table

You can view a render video of your Site and inspect the stages of rendering in a timeline, which helps with grading what your users experience. With the Main Thread Execution Timeline, it’s possible to pinpoint long-running and blocking JavaScript tasks. Lastly, assets and requests can be inspected in great detail to find performance bottlenecks.

Performance, SEO, Best Practices, Accessibility and PWA tabs provide information about passed and failed Lighthouse audits, highlighting opportunities for improvement.

The Third Party tab provides insight into how external script contributes to worsening your web performance. You can quickly analyse which third party vendors contribute most transfer size and main thread execution time to your overall scores.

Step 7: Automate your performance system

Once you have the basics covered, you could leverage the Node.js API and command-line interface to automate running tests, site management, and enable deployment tracking. Both are available on Mac, Windows and Linux.

All of the data Calibre collects is retrievable, so you can transform it to your needs and send to any services you might be using (for example: visualise performance metrics in your office with Geckoboard).

Using the Node.js API or the CLI is a powerful way to establish a reliable system that continuously monitors your performance whenever it’s necessary.


Once you have completed these steps, you can continue your journey with Calibre by discovering all features or reaching out to our technical support team for help in establishing your performance strategy.